You can't do it directly with the deco tool in one step (i.e. just keep targeting it to raise it above the layer). You will need to build a goza stair and raise it in stages, placing your goza on stacked things to raise it higher from a new "ground" level point as you go. I think Sarsmi had a tutorial on this, but I can't seem to find it. You can also use the Heritage ladders and stacked items such as the small wooden tables to be able to get your gozas up higher than the deco tool will allow you to directly raise them.
Here are some of Sarsmi's notes about using the Heritage ladders:
Heritage token ladders might help. You can place the goza mat at your feet while standing on the ladder (target yourself or your health bar to place it). Then place a new ladder on that goza mat and walk up the ladder and place again.
-Skylark